Fire is one of the most powerful disturbances of natural ecosystems because it can reshape communities. In the southern Appalachian region of the United States, fires are a re-emerging, yet still largely historical dimension of the landscape. While many aspects of wildfire effects have been elucidated in the western United States, effects of wildfire in the eastern United States remain unclear. Because fire suppression in the Great Smoky Mountains has been part of forest management practices for many decades, the plant communities present are prone to high severity fires due to the accumulation of leaf litter and plant biomass. The proximity of human communities to protected areas such as the Great Smoky Mountains National Park (GSMNP) requires fire suppression, thus the urban-wildfire interface in this region has not been extensively explored. We are investigating understory plant communities affected by the 2016 Chimney Tops 2 fire at 20 plot sites in Gatlinburg, Tennessee, and in the GSMNP. Our goal is to determine vegetation successional stages as the landscape recovers from fire, as well as the susceptibility of site locations to species dominance over time.
Results/Conclusions
In 2017, plant species richness and abundance varied throughout the 20 plot sites examined in Gatlinburg and the GSMNP. We observed highest plant abundance at no burn and natural sites and lowest abundance at high burn sites. In addition, abundance at the natural sites was 1.5 times higher than at the urban sites. The most diverse was the low/medium burn sites, followed by no burn, high burn, and reference. In 2018, patterns exhibited are different from those seen in 2017. Across all sites, there is a statistical difference between high burn compared to low/medium, no burn, and reference in richness (p= 0.0285); however, there is no difference in plant abundance (p= 0.3234) among burn severity. Between the exurban and natural areas, similar patterns arose where there was statistically lower richness in the exurban areas (p= 0.0047), but no difference in abundance (p= 0.1241). Continuation of this study will determine if disturbance across the urban and fire gradient generates new patterns of species dominance over time and whether those species will create new communities within disturbed locations. The data collected from this study allowed us to evaluate the impact of these disturbance forces on plant communities. This knowledge can be used to improve predictions of plant species composition at sites that are influenced by fire events and urban development.